Secondary batteries which are highly applicable to various products and exhibit superior electrical properties such as high energy density, etc. are commonly used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electrical power sources. The secondary battery is drawing attentions as a new energy source for enhancing energy efficiency and environment friendliness in that the use of fossil fuels can be reduced greatly and no byproduct is generated during energy consumption.
Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.2V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity.
Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of at least one battery cell first, and then configure a battery pack by using at least one battery module and adding other components.
A conventional battery module generally includes a battery cell assembly having a plurality of stacked battery cells and an ICB assembly mounted to one side of the battery cell assembly and having sensing bus bars for electrically connecting pairs of electrode leads of the plurality of battery cells.
In the conventional battery module, after the ICB assembly is mounted to one side of the battery cell assembly, a pair of electrode leads of the battery cells passing through the lead slots of the ICB assembly and sensing bus bars of the ICB assembly are connected by laser welding or the like.
Here, the lead slots of the ICB assembly are generally provided in a number correspond to the number of the pair of electrode leads of the battery cells, and the electrode leads respectively passing through the lead slots are bent to make surface contact with the sensing bus bars and welded to the sensing bus bars. At this time, the sensing bus bars are placed between electrode leads facing each other, and the facing electrode leads are bent in opposite directions toward the sensing bus bar to make surface contact with the sensing bus bar and then welded to the sensing bus bar.
However, in the conventional battery module, since the lead slots are required in the ICB assembly as much as the number of the electrode cells, the number of lead slots is increased according to the number of the electrode leads, and intervals of the lead slots are relatively narrowed. Thus, the efficiency of the assembling process may be deteriorated according to the number of electrode leads.
Also, in the conventional battery module, when the facing electrode leads are bent for welding to the sensing bus bar disposed between the facing electrode leads, the facing electrode leads are bent opposite directions toward the sensing bus bar, which demands two or more bending directions. This also acts as a factor for hindering the efficiency of the assembling process.
Therefore, in the battery module, it is required to find a way to improve the efficiency of the assembling process when the ICB assembly is assembled to the battery cell assembly.